The Purpose of this Study was to examine the anatomic differences in the upper airway according to severity of respiratory disturbance index of habitual snorers. Forty-three male habitual snorers, aged 28-68, were examined by polysomnography and divided into 4 groups according to severity determined by polysomnography. Anatomic differences in the upper airway were assessed by lateral cephalograms in upright position, and epidemiological surveys were done by using questionnaires. The obtained results were as follows : 1. All subjects were habitual snorers and 35 patients (81.4%) complained the loudness of snoring as severe as be heard outside of the room. 2. According to the results of polysomnography, the number of the primary snoring patients was 7(16.3%), mild obtrusive sleep apnea 7(16.3%), moderate 7(16.3%), and severe 22(51.2%). 3. The respiratory disturbance index (RDI) of subjects was 39.5$pm$24.4 and the body mass index(BMI) was 26.2$pm$2. 4. More inferiorly positioned hyoid bone according to the degree of respiratory disturbace index (RDI) was observed. (p<0.001) 5. The width of superior oropharyngeal airway space was according to the degree of RDI. (p<0.001)